PUB - Electro-hydrostatic actuators in primary flight control - lifetime and reliability


As part of the MODULAR project funded by the BMWK, a publication on the topic of "Robustness of electro-hydrostatic actuators" was published. It provides an insight into the state of the art of the use and robustness of electro-hydrostatic actuators in primary flight control. The publication clearly shows the existing potentials as well as the need for development of the technology.


Authors: Merkel, Amos; Duensing, Yannick; Schmitz, Katharina

More electric Aircrafts require electrically powered yet highly dynamic and robust linear flight control actuators. Electro-Hydrostatic Actuators (EHA) combine the advantages of both, the electric and the hydraulic domain. Hence, they are a highly favoured solution for the application to actuate ailerons, rudders and elevators. However, the lifetime of existing systems is limited due to early pump failure, limiting the use to backup-actuators in present systems. This paper gives an overview of the EHA technologies in primary flight control. From the special operating conditions in primary flight control application, the sources of pump failure are derived. The authors highlight the challenges and characteristics in pump design for EHA applications. Furthermore, possible countermeasures are discussed. In order to find the dominant damage relevant operating conditions and areas of wear of specific systems, the experimental design for a sequential endurance test campaign is presented. This test campaign aims to allow the distinction of wear contribution to specific areas and operating modes in future. Finally, the authors highlight possible optimization strategies for reducing wear and increasing reliability by focusing on understanding and predicting pump failure in aerospace EHAs.